The present invention relates to an ozone storage/recovery method and a system therefor, capable of generating ozone with use of low-priced night electricity in the main, storing it, and discharging it as required.
Ozone is a clean oxidizing agent that is free from secondary environmental pollution and easy to handle, and therefore, is widely used in the fields of sterilization, cleaning, oxidative bleaching, etc.
In general, however, ozone is decomposed so easily that it cannot be stored in a gas cylinder or the like. Conventionally, therefore, ozone is used hot from a silent-discharge ozone generator, ozone generator with an ultraviolet lamp, water-electrolysis ozone generator, etc.
More specifically, the ozone generator is installed on the scene of use, and ozone is obtained by operating the generator only when it is needed. According to this method, however, it is hard for users to cope with load fluctuations.
Ozone is produced by using the silent-discharge ozone generator or water-electrolysis ozone generator in the main. However, the cost of power supply for operating these generators accounts for a high percentage in the unit cost of ozone manufacture. Since the demand for ozone is restricted by time and fluctuates, on the other hand, there has been a request for the development of an ozone storage device from which an ozone-containing gas with a given concentration can be taken out as required.
To attain this, the gas may possibly be liquefied when it is stored into an adsorbent so that it can be taken out when needed. However, these storage methods have the following problems.
In general, ozone easily decomposes and liquefying it requires great energy, so that the liquefying method is impractical.
Silica gel is a well-known ozone adsorbent. Its ozone adsorptivity is so low. Also, the silica gel strongly adsorbs water, if any, in advance of ozone. Thus, water is stored in silica gel, so that the ozone adsorption amount is lowered correspondingly. Further, a sizable amount of ozone decomposes while it is being adsorbed by silica gel, so that the ozone recovery is reduced considerably. For the long run, furthermore, silica gel may possibly be powdered due to the adsorption of water. In consequence, the ozone storage apparatus that uses silica gel lacks in utility.